Eye-mountable device to provide automatic accommodation and method of making same

ABSTRACT

An eye-mountable device (EMD) includes a lens enclosure, liquid crystal material, first and second electrodes, a substrate, and a controller. The lens enclosure includes a first encapsulation layer and a second encapsulation layer sealed to the first encapsulation layer. The liquid crystal material is disposed across a central region of the lens enclosure. The first electrode is disposed within the lens enclosure between the first encapsulation layer and the liquid crystal material. The second electrode is disposed within the lens enclosure between the second encapsulation layer and the liquid crystal material. The substrate is disposed within the EMD. The controller is disposed on the substrate and electrically coupled to the first and second electrodes to apply a voltage across the liquid crystal material.

CROSS REFERENCE TO RELATED APPLICATIONS

The present patent application is a continuation of U.S. applicationSer. No. 15/631,815 filed on Jun. 23, 2017, which is a continuation ofU.S. application Ser. No. 14/710,332 (U.S. Pat. No. 9,690,118) filed onMay 12, 2015, which claims priority under the provisions of 35 U.S.C. §119(e) to U.S. Provisional Application No. 62/012,005 filed Jun. 13,2014, to U.S. Provisional Application No. 62/012,017 filed Jun. 13,2014, and to U.S. Provisional Application No. 62/012,033 filed Jun. 13,2014, all of which contents are hereby incorporated by reference.

BACKGROUND 1. Technical Field

This disclosure relates generally to the field of optics, and inparticular but not exclusively, relates to contact lenses.

2. Background Art

Accommodation is a process by which the eye adjusts its focal distanceto maintain focus on objects of varying distance. Accommodation is areflex action, but can be consciously manipulated. Accommodation iscontrolled by contractions of the ciliary muscle. The ciliary muscleencircles the eye's elastic lens and applies a force on the elastic lensduring muscle contractions that change the focal point of the elasticlens.

As an individual ages, the effectiveness of the ciliary muscle degrades.Presbyopia is a progressive age-related loss of accommodative orfocusing strength of the eye, which results in increased blur at neardistances. This loss of accommodative strength with age has been wellstudied and is relatively consistent and predictable. Presbyopia affectsnearly 1.7 billion people worldwide today (110 million in the UnitedStates alone) and that number is expected to substantially rise as theworld's population ages. Techniques and devices that can helpindividuals offset the effects of Presbyopia are increasingly in demand.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments of the present invention are illustrated by wayof example, and not by way of limitation, in the figures of theaccompanying drawings and in which:

FIG. 1 is a functional block diagram of an eye-mountable device thatprovides auto-accommodation and an external reader for interacting withthe eye-mountable device, in accordance with an embodiment.

FIG. 2A is a top view illustration of an eye-mountable device, inaccordance with an embodiment.

FIG. 2B is a perspective view illustration of an eye-mountable device,in accordance with an embodiment.

FIG. 3 is an exploded perspective view that illustrates the variouscomponents and layers of an eye-mountable device, in accordance with anembodiment.

FIG. 4 is a flow chart illustrating a process for fabricating aneye-mountable device with a liquid crystal accommodation actuator, inaccordance with an embodiment.

FIG. 5 shows cross-sectional views of a process to fabricate aneye-mountable device according to an embodiment.

FIG. 6 shows cross-sectional views of respective eye-mountable deviceseach according to a corresponding embodiment.

FIGS. 7A-7C illustrate configurations of conductive electrodes relativeto a liquid crystal layer within the eye-mountable device, in accordancewith an embodiment.

FIG. 8 is a profile view that illustrates connections between a ringsubstrate and conductive electrodes within an eye-mountable device, inaccordance with an embodiment.

DETAILED DESCRIPTION

Embodiments of a system, apparatus, and method of fabrication for aneye-mountable device (or “EMD”) including an accommodation actuator aredescribed herein. In the following description numerous specific detailsare set forth to provide a thorough understanding of the embodiments.One skilled in the relevant art will recognize, however, that thetechniques described herein may be practiced without one or more of thespecific details, or with other methods, components, materials, etc. Inother instances, well-known structures, materials, or operations are notshown or described in detail to avoid obscuring certain aspects.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present invention. Thus, theappearances of the phrases “in one embodiment” or “in an embodiment” invarious places throughout this specification are not necessarily allreferring to the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments.

Described herein is a smart contact lens or other eye-mountable devicethat comprises an electrically activated lens including an accommodationactuator for adjusting the focal distance of the contact lens. In someembodiments, the accommodation is automatically adjusted in real-timebased upon a user's gazing direction. The accommodation actuator isdisposed in a center region of the smart contact lens (e.g., covering atleast the foveal vision). As such, it is desirable that structuresand/or fabrication processes aid in the positioning of an accommodationactuator—e.g., relative to electrodes and/or other circuitry that is tosupport operation of the accommodation actuator.

The accommodation actuator may be implemented with a layer of liquidcrystal (LC) material, and may require electrodes to electronicallycontrol the accommodation actuator. Accordingly, electrical, structuraland/or other isolation may need to be provided—e.g., between theelectrodes or between the liquid crystal and control circuitry of theEMD. Embodiments of the instant disclosure mitigate drawbacks that, forexample, are associated with fabrication of an accommodation actuatorseparately from other lens structures. Certain embodiments variouslyallow for an accommodation actuator (e.g., including a LC material andadjoining layers or polyimide or other alignment material) to be builtup, by successive processing steps, on an enclosure layer that, forexample, is to form at least part of an exterior of a lens enclosure.Such an enclosure layer may be subsequently sealed to another enclosurelayer to form the lens enclosure, where the accommodation actuator issurrounded by, and sealed with, a pinch-off region of the lensenclosure.

Embodiments of the eye-mountable device may include a power supply,control electronics, an accommodation actuator, a gaze direction sensorsystem, and an antenna all embedded within a lens enclosure formed to becontact mounted to an eye (e.g., shaped to be removeably mounted to acornea and allow eyelid motion to open and close). In one embodiment,the control electronics are coupled to monitor the sensor system toidentify gaze direction/focal distance, manipulate the accommodationactuator to control the optical power of the eye-mountable device, andprovide wireless communications with an external reader. In someembodiments, the power supply may include charging circuitry forcontrolling inductive wireless charging of an embedded battery.

The lens enclosure may be fabricated of a variety of materialscompatible for direct contact with a human eye, such as a polymericmaterial, a hydrogel, PMMA, silicone based polymers (e.g.,fluoro-silicon acrylate), or otherwise. The electronics may be disposedupon a substrate—e.g., having a ring shape—embedded within the lensenclosure near its periphery to avoid interference with incident lightreceived closer to the central region of the cornea. The sensor systemmay be arranged on the substrate to face outward towards the eyelids todetect the gaze direction/focal distance based upon the amount andposition of eyelid coverage over the sensor system. As the eyelids coverdifferent portions of the sensor system, this changes a characteristic(e.g., its capacitance), which may be measured to determine gazedirection and/or focal distance.

In some embodiments, the gaze direction/focal distance information maythen be used to determine the amount of accommodation to be applied viaa see-through accommodation actuator positioned in a central portion ofthe lens enclosure. The accommodation actuator is coupled to thecontroller to be electrically manipulated thereby via the application ofa voltage across a pair of electrodes. For example, the accommodationactuator maybe implemented with a LC cell that changes its index ofrefraction in response to an applied electrical bias signal across theelectrodes. In other embodiments, the accommodation actuator may beimplemented using other types of electro-active materials such aselectro-optic materials that vary refractive index in the presence of anapplied electric field or electro-mechanical structures that change theshape of a deformable lens. Other example structures that may be used toimplement the accommodation actuator include electro-wetting optics,micro-electro-mechanical systems, or otherwise.

Features of various embodiments are described herein in the context of aflexible eye-mountable accommodating lens device including anaccommodation actuator comprising a LC layer, wherein an opticalstrength (e.g., corresponding to a particular focal length) of thedevice may be changed based on capacitive gaze tracking mechanisms.However, such description may be extended to additionally oralternatively apply to any of a variety of other accommodating opticaldevices that may operate in or on an eye of a user. For example, certainembodiments are not limited with respect to a particularflexibility/rigidity of the eye-mountable device and/or a particularmechanism (e.g., LC element or other) by which an accommodation actuatorchanges an optical strength of the device. Furthermore, some embodimentsare not limited with respect to a capacitive gaze tracking,photodetector gaze tracking of other technique that may be used todetermine whether a change in optical strength is to take place.

FIG. 1 is a functional block diagram of an eye-mountable device (EMD)100 with gaze tracking for auto-accommodation along with an externalreader 105, in accordance with an embodiment of the disclosure. Theexposed portion of EMD 100 is a flexible lens enclosure 110 formed to becontact-mounted to a corneal surface of an eye. A substrate 115 isembedded within or surrounded by flexible lens enclosure 110 to providea mounting surface for a power supply 120, a controller 125, a sensorsystem 135, an antenna 140, and various interconnects 145 and 150. Anaccommodation actuator 130 is embedded within flexible lens enclosure110 and coupled to controller 125 to provide auto-accommodation to thewearer of EMD 100. The illustrated embodiment of power supply 120includes an energy harvesting antenna 155, charging circuitry 160, and abattery 165. The illustrated embodiment of controller 125 includescontrol logic 170, accommodation logic 175, and communication logic 180.The illustrated embodiment of reader 105 includes a processor 182, anantenna 184, and memory 186.

Controller 125 is coupled to receive feedback control signals fromsensor system 135 and further coupled to operate accommodation actuator130. Power supply 120 supplies operating voltages to the controller 125and/or the accommodation actuator 130. Antenna 140 is operated by thecontroller 125 to communicate information to and/or from EMD 100. In oneembodiment, antenna 140, controller 125, power supply 120, and sensorsystem 135 are all situated on the embedded substrate 115. In oneembodiment, accommodation actuator 130 is embedded within a centerregion of flexible lens enclosure 110, but is not disposed on substrate115. Because EMD 100 includes electronics and is configured to becontact-mounted to an eye, it is also referred to herein as anophthalmic electronics platform, a contact lens, or a smart contactlens.

To facilitate contact-mounting, the flexible lens enclosure 110 may havea concave surface configured to adhere (“mount”) to a moistened cornealsurface (e.g., by capillary forces with a tear film coating the cornealsurface). Additionally or alternatively, the EMD 100 may be adhered by avacuum force between the corneal surface and flexible lens enclosure 110due to the concave curvature. While mounted with the concave surfaceagainst the eye, the outward-facing surface of flexible lens enclosure110 may have a convex curvature that is formed to not interfere witheye-lid motion while the EMD 100 is mounted to the eye. For example,flexible lens enclosure 110 may be a substantially transparent curveddisk shaped similarly to a contact lens.

Flexible lens enclosure 110 may include one or more biocompatiblematerials, such as those employed for use in contact lenses or otherophthalmic applications involving direct contact with the cornealsurface. Flexible lens enclosure 110 may optionally be formed in partfrom such biocompatible materials or may include an outer coating withsuch biocompatible materials. Flexible lens enclosure 110 may includematerials configured to moisturize the corneal surface, such ashydrogels and the like. Flexible lens enclosure 110 is a deformable(“non-rigid”) material to enhance wearer comfort. In some instances,flexible lens enclosure 110 may be shaped to provide a predetermined,vision-correcting optical power, such as can be provided by a contactlens. Flexible lens enclosure 110 may be fabricated of various materialsincluding a polymeric material, a hydrogel, PMMA, silicone basedpolymers (e.g., fluoro-silicon acrylate), or otherwise.

Substrate 115 includes one or more surfaces suitable for mounting sensorsystem 135, controller 125, power supply 120, and antenna 140. Substrate115 may be employed both as a mounting platform for chip-based circuitry(e.g., by flip-chip mounting) and/or as a platform for patterningconductive materials (e.g., gold, platinum, palladium, titanium, copper,aluminum, silver, metals, other conductive materials, combinations ofthese, etc.) to create electrodes, interconnects, antennae, etc. In someembodiments, substantially transparent conductive materials (e.g.,indium tin oxide or the flexible conductive materials discussed below)may be patterned on substrate 115 to form circuitry, electrodes, etc.For example, antenna 140 may be formed by depositing a pattern of goldor another conductive material on substrate 115. Similarly,interconnects 145 and 150 may be formed by depositing suitable patternsof conductive materials on substrate 115. A combination of resists,masks, and deposition techniques may be employed to pattern materials onsubstrate 115. Substrate 115 may be a relatively rigid material, such aspolyethylene terephthalate (“PET”) or another material sufficient tostructurally support the circuitry and/or electronics within enclosurematerial 110. EMD 100 may alternatively be arranged with a group ofunconnected substrates rather than a single substrate. For example,controller 125 and power supply 120 may be mounted to one substrate,while antenna 140 and sensor system 135 are mounted to another substrateand the two may be electrically connected via interconnects.

Although certain embodiments are not limited in this regard, substrate115 may be shaped as a flattened ring with a radial width dimensionsufficient to provide a mounting platform for the embedded electronicscomponents. Substrate 115 may have a thickness sufficiently small toallow the substrate to be embedded in flexible lens enclosure 110without adversely influencing the profile of EMD 100. Substrate 115 mayhave a thickness sufficiently large to provide structural stabilitysuitable for supporting the electronics mounted thereon. For example,substrate 115 may be shaped as a ring with a diameter of about 10millimeters, a radial width of about 1 millimeter (e.g., an outer radius1 millimeter larger than an inner radius), and a thickness of about 50micrometers. Substrate 115 may optionally be aligned with the curvatureof the eye-mounting surface of EMD 100 (e.g., convex surface). Forexample, substrate 115 may be shaped along the surface of an imaginarycone between two circular segments that define an inner radius and anouter radius. In such an example, the surface of substrate 115 along thesurface of the imaginary cone defines an inclined surface that isapproximately aligned with the curvature of the eye mounting surface atthat radius.

In some embodiments, power supply 120 and controller 125 (and thesubstrate 115) may be positioned away from the center of EMD 100 andthereby avoid interference with light transmission to the eye throughthe center of EMD 110. In contrast, accommodation actuator 130 may becentrally positioned to apply optical accommodation to the lighttransmitted to the eye through the center of enclosure material 110. Forexample, where EMD 100 is shaped as a concave-curved disk, substrate 115may be embedded around the periphery (e.g., near the outercircumference) of the disk. In some embodiments, sensor system 135includes one or more discrete capacitance sensors that are peripherallydistributed to sense the eyelid overlap.

In the illustrated embodiment, power supply 120 includes a battery 165to power the various embedded electronics, including controller 125.Battery 165 may be inductively charged by charging circuitry 160 andenergy harvesting antenna 155. In one embodiment, antenna 140 and energyharvesting antenna 155 are independent antennae, which serve theirrespective functions of energy harvesting and communications. In anotherembodiment, energy harvesting antenna 155 and antenna 140 are the samephysical antenna that are time shared for their respective functions ofinductive charging and wireless communications with reader 105. Chargingcircuitry 160 may include a rectifier/regulator to condition thecaptured energy for charging battery 165 or directly power controller125 without battery 165. Charging circuitry 160 may also include one ormore energy storage devices to mitigate high frequency variations inenergy harvesting antenna 155. For example, one or more energy storagedevices (e.g., a capacitor, an inductor, etc.) may be connected tofunction as a low-pass filter.

Controller 125 contains logic to choreograph the operation of the otherembedded components. Control logic 170 controls the general operation ofEMD 100, including providing a logical user interface, power controlfunctionality, etc. Accommodation logic 175 includes logic formonitoring feedback signals from sensor system 135, determining thecurrent gaze direction or focal distance of the user, and manipulatingaccommodation actuator 130 in response to provide the appropriateaccommodation. The auto-accommodation may be implemented in real-timebased upon feedback from the gaze tracking, or permit user control toselect specific accommodation regimes (e.g., near-field accommodationfor reading, far-field accommodation for regular activities, etc.).Communication logic 180 provides communication protocols for wirelesscommunication with reader 105 via antenna 140. In one embodiment,communication logic 180 provides backscatter communication via antenna140 when in the presence of an electromagnetic field 171 output fromreader 105. In one embodiment, communication logic 180 operates as asmart wireless radio-frequency identification (“RFID”) tag thatmodulates the impedance of antenna 140 for backscatter wirelesscommunications. The various logic modules of controller 125 may beimplemented in software/firmware executed on a general purposemicroprocessor, in hardware (e.g., application specific integratedcircuit), or a combination of both.

EMD 100 may include various other embedded electronics and logicmodules. For example, a light source or pixel array may be included toprovide visible feedback to the user. An accelerometer or gyroscope maybe included to provide positional, rotational, directional oracceleration feedback information to controller 125.

FIGS. 2A and 2B illustrate two views of an EMD 200, in accordance withan embodiment of the disclosure. FIG. 2A is a top view of EMD 200 whileFIG. 2B is a perspective view of the same. EMD 200 is one possibleimplementation of EMD 100 illustrated in FIG. 1. The illustratedembodiment of EMD 200 includes a flexible lens enclosure 210, a ringsubstrate 215, a power supply 220, a controller 225, an accommodationactuator 230, a capacitive sensor system 235, and an antenna 240. Itshould be appreciated that FIGS. 2A and 2B are not necessarily drawn toscale, but have been illustrated for purposes of explanation only indescribing the arrangement of the example EMD 200.

Flexible lens enclosure 210 of EMD 200 is shaped as a curved disk.Flexible lens enclosure 210 is formed with one side having a concavesurface 211 suitable to fit over a corneal surface of an eye. Theopposite side of the disk has a convex surface 212 that does notinterfere with eyelid motion while EMD 200 is mounted to the eye. In theillustrated embodiment, a circular or oval outer side edge 213 connectsthe concave surface 211 and convex surface 212.

EMD 200 may have dimensions similar to a vision correction and/orcosmetic contact lenses, such as a diameter of approximately 1centimeter, and a thickness of about 0.1 to about 0.5 millimeters.However, the diameter and thickness values are provided for explanatorypurposes only. In some embodiments, the dimensions of EMD 200 areselected according to the size and/or shape of the corneal surface ofthe wearer's eye. Flexible lens enclosure 210 may be formed with acurved shape in a variety of ways. For example, techniques similar tothose employed to form vision-correction contact lenses, such as heatmolding, injection molding, spin casting, etc. may be employed to formflexible lens enclosure 210.

Ring substrate 215 is embedded within flexible lens enclosure 210. Ringsubstrate 215 may be embedded to be situated along the outer peripheryof flexible lens enclosure 210, away from the central region whereaccommodation actuator 230 is positioned. In the illustrated embodiment,ring substrate 215 encircles accommodation actuator 230. Ring substrate215 does not interfere with vision because it is too close to the eye tobe in focus and is positioned away from the central region whereincident light is transmitted to the light-sensing portions of the eye.In some embodiments, ring substrate 215 may optionally be formed of atransparent material to further mitigate effects on visual perception.Ring substrate 215 may be shaped as a flat, circular ring (e.g., a diskwith a centered hole). The flat surface of ring substrate 215 (e.g.,along the radial width) is a platform for mounting electronics and forpatterning conductive materials to form electrodes, antenna(e), and/orinterconnections.

Capacitive sensor system 235 is distributed about EMD 200 to senseeyelid overlap in a manner similar to capacitive touch screens. Bymonitoring the amount and position of eyelid overlap, feedback signalsfrom capacitive sensor system 235 may be measured by controller 225 todetermine the approximate gaze direction and/or focal distance. In theillustrated embodiment, capacitive sensor system 235 is formed by aseries of parallel coupled discrete capacitive elements. Otherimplementations may be used.

Accommodation actuator 230 is centrally positioned within flexible lensenclosure 210 to affect the optical power of EMD 200 in the user'scenter of vision. A pinch-off region 232 may be disposed betweenaccommodation actuator 230 and ring substrate 215 to provide electricalisolation from at least some circuitry of ring substrate 215. In variousembodiments, accommodation actuator 230 includes an element that changesits index of refraction under the influence of flexible conductiveelectrodes manipulated by controller 225. By changing its refractiveindex, the net optical power of the curved surfaces of EMD 200 isaltered, thereby applying controllable accommodation. Accommodationactuator 230 may be implemented using a variety of differentoptoelectronic elements. For example, accommodation actuator 230 may beimplemented using a layer of liquid crystal (e.g., a LC cell) disposedin the center of flexible lens enclosure 210. In other embodiments,accommodation actuator 230 may be implemented using other types ofelectro-active optical materials such as electro-optic materials thatvary refractive index in the presence of an applied electric field.Accommodation actuator 230 may be a distinct device embedded withinenclosure material 210 (e.g., LC cell), or a bulk material having acontrollable refractive index. In yet another embodiment, accommodationactuator 230 may be implemented using a deformable lens structure thatchanges shape under the influence of an electrical signal. Accordingly,the optical power of EMD 200 is controlled by controller 225 with theapplication of electric signals via one or more electrodes extendingfrom controller 225 to accommodation actuator 230.

FIG. 3 is an explode perspective view illustrating an EMD 300, inaccordance with an embodiment of the disclosure. EMD 300 is one possibleimplementation of EMDs 100 or 200, but the exploded perspectiveillustration shows additional details of various components. Theillustrated embodiment of EMD 300 includes a flexible lens enclosureincluding an anterior layer 305 and a posterior layer 310, an anteriorflexible conductive electrode (ANT) 315, a posterior flexible conductiveelectrode (POST) 320, a liquid crystal layer 325, a ring substrate 330,a power supply 335, a controller circuit 340, an anterior contact pad345, and a posterior contact pad 350 (hidden in FIG. 3). Collectively,the ANT 315, LC layer 325, and POST 320 form an accommodation actuatorthat is manipulated under the influence of controller circuit 340. Theillustrated embodiment of ANT 315 includes a connection tab 360 and theillustrated embodiment of POST 320 includes a connection tab 365.

ANT 315 and POST 320 are transparent electrodes that electricallymanipulate LC layer 325 via the application of a voltage across theelectrodes. ANT 315 and POST 320 are flexible conductors thatsubstantially maintain their conductivity even in the presence ofcyclical mechanical stressing including folding and bending. ANT 315 andPOST 320 are formed from a liquid conductor material that is cured onto,and therefore conform to, the curved surfaces of anterior layer 305 andposterior layer 310, respectively. ANT 315 and POST 320 may be appliedto anterior layer 305 and posterior layer 310, respectively, using avariety of techniques. For example, a liquid conductor materialincluding conductive epoxy, conductive polymer, conductive silicon,evaporated metal or other conductive material may be spray coated,stamped, shadow masked or otherwise disposed to form electrodestructures to operate an accommodation actuator. In one embodiment, theliquid conductor material is spray coated on the inside concave surfaceof anterior layer 305 using a conforming concave stencil and is alsospray coated on the inside convex surface of posterior layer 310 using aconforming convex stencil. In other embodiments, the spray coating maybe actively controlled without use of stencils, or applied afterapplication of a temporary mask. In yet other embodiments, the liquidconductor material is coated onto a stamp with a conforming shapedsurface that is then pressed to anterior layer 305 or posterior layer310 to transfer the liquid conductor material. Other applicationtechniques may also be used to form and position ANT 315 and POST 320onto anterior layer 305 and posterior layer 310, respectively. In oneembodiment, ANT 315 and POST 320 are formed to achieve a desired totalsheet resistance. Target sheet resistances may range between 100ohms/square to 2000 ohms/square (e.g., 190 ohms/square). Of course,other target sheet resistances outside this range may also be used.

LC layer 325 may be disposed between anterior layer 305 and posteriorlayer 310 in a central region of the EMD 300. Formation of LC layer 325may include spraying, spinning, masking, stamping, stenciling, and/orother operations adapted from conventional fabrication techniques. LClayer 325 may comprise, for example,poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (or PEDOT:PSS)or any of various other liquid crystals that provide for variablerefractive index characteristics. In an embodiment, LC layer 325 isisolated electrically from at least some circuitry of ring substrate325. Additionally or alternatively, LC layer 325 may be disposed betweenANT 315 and POST 320 in the central region of EMD 300.

FIG. 4 is a flow chart illustrating a process 400 for fabricating anEMD—e.g., one of eye-mountable devices 100, 200, or 300—in accordancewith an embodiment of the disclosure. The order in which some or all ofthe process blocks appear in process 400 should not be deemed limiting.Rather, one of ordinary skill in the art having the benefit of thepresent disclosure will understand that some of the process blocks maybe executed in a variety of orders not illustrated, or even in parallel.Features of process 400 are described herein with reference tofabrication of EMD 300. However, such description may be extended toadditionally or alternatively apply to fabrication of any of variousother EMDs having features set forth herein.

In process blocks 405 and 410, anterior layer 305 and posterior layer310 are formed as separate layers of a lens enclosure. Anterior layer305 and posterior layer 310 may be formed using molds that are spraycoated or injected with a flexible, transparent material. The flexible,transparent material may include any of a polymeric material, ahydrogel, PMMA, silicone based polymers (e.g., fluoro-silicon acrylate),or otherwise.

Although certain embodiments are not limited in this regard, anteriorlayer 305 and/or posterior layer 310 may be treated to form reactivesurfaces for improved bonding to the ANT 315 and POST 320. For example,anterior layer 305 and posterior layer 310 may be plasma treated in ahighly ionizing environment that causes the inside surfaces of anteriorlayer 305 and posterior layer 310 to be chemically reactive.

In a process block 415, conductor material that forms ANT 315 and POST320 is deposited onto the concave surface of anterior layer 305 anddeposited onto the convex surface of posterior layer 310. In oneembodiment, the deposition of the liquid conductor material may be spraycoated over stencils that conform to the concave and convex surfaces. Inyet another embodiment, the liquid conductive material is applied tostamps with curved surfaces that conform to the concave and convexsurfaces of anterior layer 305 and posterior layer 310, respectively.The coated stamps are then pressed against the inside surfaces ofanterior layer 305 and posterior layer 310 to transfer the ink patternthereto. After application of the liquid conductor material, it may becured and/or annealed—e.g., with heat.

The conductor material may include a conductive epoxy (e.g., any ofvarious conductive silicones), evaporated metal (gold, aluminum), acolloidal solution of conductive particles (e.g., nanotubes ornanowires) and/or the like. Deposition of the conductor material mayinclude forming any of a variety of conductive structures including, butnot limited to, one or more gold wires, silver nanowires, an indium tinoxide thin film, etc. In some embodiments, various solvents (e.g.,alcohol), surfactants, or dilutants may be added to the liquid conductormaterial to improve the uniform coating and adhesion of ANT 315 and POST320 to anterior layer 305 and posterior layer 310, respectively.

Next, ring substrate 330, including power supply 335 and controllercircuit 340, are positioned between the anterior layer 305 and theposterior layer 310—e.g., including positioning the substrate over theconvex surface of posterior layer 310 (process block 420). Before orduring the positioning at 420, a conductive adhesive may be applied tocontact pads on ring substrate 330 in preparation for electricalcoupling of ring substrate 330 to one or both of ANT 315 and POST 320.The positioning at 420 may include aligning connection tabs 360, 365each with a respective contact pad of ring substrate 330—e.g., whereconnection tabs 360, 365 are radially offset from one another.

In a process block 425, an accommodation actuator structure is disposedbetween the anterior layer and the posterior layer. For example, aliquid crystal material may be dispensed around (e.g., includingdispensing on) the center region of the concave surface of anteriorlayer 305 and covers over ANT 315. In one embodiment, the LC material isdispensed over a larger area such that LC layer 325 covers a greaterarea than either ANT 315 or POST 320.

In a process block 430, the two halves (anterior layer 305 and posteriorlayer 310) of the lens enclosure are pressed together and sealed. Forexample, an amount of enclosure material may be added between anteriorlayer 305 and posterior layer 310 in a region around a circumference ofthe LC material. Curing of this material between the anterior andposterior layers may result in a pinch-off region being formed aroundthe LC material. In one embodiment, more enclosure material is alsoadded to the bottom edge or rim of the mated anterior layer 305 andposterior layer 310 to form the seal. Curing of this additionalenclosure material may seal the substrate in a peripheral region betweenanterior layer 305 and posterior layer 310. Finally, the eye-mountabledevice or smart contact lens is packaged into a sealed container of lenssolution for distribution (process block 435).

It will be appreciated that the particular order of the operations shownfor method 400 is not limiting on some embodiments. By way ofillustration and not limitation, some or all portions of anaccommodation actuator, electrode structures and/or a ring substrate maybe variously fabricated and combined with one another, according todifferent embodiments, as a separate component prior to assembly of sucha component with one or both lens enclosure layers.

FIG. 5 illustrates cross-sectional detail views of processing tofabricate an eye-mountable device according to an embodiment.Fabrication processes represented in FIG. 5 may include some or all ofthe features of operation 400, for example. Detail view 500 illustratesformation of a posterior layer 504 (e.g., layer 310) on a mold 502, anddetail view 510 illustrates formation of an anterior layer 514 (e.g.,layer 305) on a mold 512.

One or each of layers 504, 510 may be comprised of one of a silicone,silicone hydrogel, hydrogel, rigid gas permeable (RGP) material, rigidplastic (e.g., polycarbonate), polymethyl methacrylate (PMMA),polymerized acrylate. Although certain embodiments are not limited inthis regard, layers 504, 510 may be flexible, in some embodiments. Inone illustrative embodiment, one or each of layers 504, 510 have adiameter between 11 and 14 mm in size. Alternatively or in addition, oneor each of layers 504, 510 is between 20 microns and 150 microns (e.g.,between 20 microns and 100 microns) thick. However, such dimensions mayvary in different embodiments according to implementation specificdetails.

Formation of layers 504, 514 may include some or all of the features ofthe forming at 405, 410, for example. In an embodiment, a recess (notshown)—e.g., 0.1 to 50 um deep—is shaped in a concave side 534 ofanterior layer 514, or in a recess in a convex side 524 of posteriorlayer 504, to aid in the formation of a LC layer of an accommodationactuator element. The shaping of such a recess may include pressing andcuring between two molds the enclosure material of one of layers 504,514.

Detail view 520 illustrates a flexible electrode 522 (e.g., electrode320) deposited on convex surface 524 of posterior layer 504, and detailview 530 illustrates a flexible electrode 532 (e.g., electrode 315)deposited on concave surface 534 of posterior layer 514. Formation ofone or each of electrodes 522, 532 may including spraying, stamping,shadow masking, evaporating or otherwise depositing a conductive epoxy(e.g., a conductive silicone), a metal (e.g., gold, aluminum, silver,etc.) or other conductive material. The resulting electrodes 522, 532may include metal wires, nanowires, indium tin oxide thin films or othersuch conductive structures to operate an accommodation actuator. In anembodiment, one or each of flexible electrodes 522, 532 has a thicknessbetween 10 nm and 10 microns and a diameter between 2 mm and 3 mm.However, such thicknesses may vary according to implementation specificdetails. In some embodiments, a flexible electrode has a main bodyportion and a tab portion (not shown), extending from the main bodyportion, where the main body portion is to be aligned with a LC layer ofan accommodation actuator, and the tab portion is to extend through apinch-off region that separates the LC layer from a substrate havingintegrated circuitry disposed therein and/or thereon.

Detail view 540 illustrates placement of such a substrate (e.g., ringsubstrate 330)—e.g., including the illustrative control circuitry 542and antenna 544—on posterior layer 504. In another embodiment, thesubstrate may instead be initially placed on surface 534. Detail view550 shows deposition of a LC layer 554 on a concave side of anteriorlayer 514. Deposition of the LC layer 554 may be including operationsadapted from conventional shadow mask, stamping or other fabricationtechniques. In an embodiment, an accommodation actuator structure (e.g.,a LC layer) comprises, or adjoins, isolation layers providing at leastsome isolation that prevents or limits one or more conductive pathsbetween a pinch-off region and electrode structures. For example, atleast partially dielectric alignment layers (not shown) of theaccommodation actuator may be disposed on opposite sides of LC layer554. The LC layer 554 may have a thickness of between 0.1 um and 50 umand/or a diameter of between 4 mm and 10 mm. However, such dimensionsare merely illustrative and not limiting on certain embodiments.

Detail view 560 shows respective structures represented in detail views540, 550 having been aligned and brought into contact with each other.In some embodiments, one or both of surfaces 524, 534 may bepretreated—e.g., with a plasma—to improve adhesion between the two.Layers 504, 514 may then be sealed to form a flexible enclosure, wherean accommodation actuator 562 is located within a central region of theflexible enclosure. A perimeter of the central region may be defined atleast in part by a pinch-off region 564 where layers 504, 514 areadjacent to (e.g., physically contact) one another.

For example, an additional amount of contact lens material—e.g., asilicone elastomer, a silicone hydrogel or the like—may be disposedaround LC layer 554 to aid in adhering layers 504, 514. Curing of suchadditional material (e.g., by heat or ultraviolet light) may result in asealing of the accommodation actuator within the central region aroundwhich pinch-off region 564 is disposed. In some embodiments, contactlens material may also be applied at an edge region around one of layers504, 514, where this additional material is also cured to seal the ringsubstrate in a region of the lens enclosure between pinch-off region 564and the respective edges of layers 504, 514.

The electrodes 522, 532 may be separated from one another in pinch-offregion 564. For example, in one illustrative embodiment, conductivelayers 522, 532 have a 6 mm diameter, and the pinch-off region has a 7mm diameter, where the LC layer 554 provides for separation of theconductive layers 522, 532 in the central region around which pinch-offregion 564 is formed.

FIG. 6 show cross-sectional detail views 600, 650 of eye-mountabledevices each according to a respective embodiment. For example, detailview 600 shows a posterior encapsulation layer 610 sealed with ananterior encapsulation layer 620 to form a flexible lens enclosure. Acentral region of the flexible lens enclosure is defined at least inpart by a pinch-off region 625 that extends around a perimeter of thecentral region. The pinch-off region 625 may serve as a seal to hold anaccommodation actuator 615 within the central region. In someembodiments, a peripheral region 630 is located around a periphery ofpinch-off region 625—e.g., where peripheral region 630 extends frompinch-off region 625 to the respective circumferential edges ofencapsulation layers 610, 620. Peripheral region 630 may include acontact lens material that is disposed and cured to aid in sealing ofencapsulation layers 610, 620 with one another. A substrate 635, havingintegrated circuitry disposed thereon, may be disposed betweenencapsulation layers 610, 620 within peripheral region 630

In detail view 600, a recess is formed in a concave surface of anteriorencapsulation layer 620 to aid in the positioning of accommodationactuator 615 during fabrication processing (e.g., according to method400). In another embodiment, an encapsulation layer may additionally oralternatively be deformed to aid in the formation of a pinch-off region.By way of illustration and not limitation, detail view 650 shows aposterior encapsulation layer 660 sealed with an anterior encapsulationlayer 670 to form a flexible lens enclosure, wherein an accommodationactuator is disposed between encapsulation layers 660, 670 within acentral region of the eye-mountable device. Respective portions of theencapsulation layers 660, 670 may adjoin one another to form a pinch-offregion 680 that defines at least in part a perimeter of the centralregion. A pinch-off region such as region 680 may be formed at least inpart by a layer of a lens material, the thickness of which extends froma flexible conductor to an exterior surface of the EMD. For example, apinch-off region may be formed by anterior and posterior layers of lensmaterial that each extend from a respective flexible conductor to adifferent respective exterior side of the EMD. The exterior surface ofone such layer of lens material may be deformed in an area over thepinch-off region. As illustrated in detail view 650, a pinch-off region680 may be formed at least in part by a flat or convex portion of anotherwise concave surface (e.g., the posterior surface) of an anteriorencapsulation layer such as layer 670.

The pinch-off region 680 may separate a LC layer 665 from circuitry 685(e.g., of ring substrate 330) that is disposed between encapsulationlayers 660, 670 in a peripheral region of the flexible lens enclosure.As shown in detail view 650, the central region formed by encapsulationlayers 660, 670 may taper in a direction extending toward pinch-offregion 680. Alternatively or in addition, the peripheral regionincluding integrated circuitry 685 may taper in a direction extendingtoward pinch-off region 680.

The accommodation actuator may comprise, or adjoin, isolation layersdisposed between respective portions of an accommodation actuatorstructure (e.g., a liquid crystal layer) and a flexible conductor. Forexample, the accommodation actuator may include alignment layers 674 a,674 b and LC layer 665. One or each of alignment layers 674 a, 674 b mayhave a thickness of 10 nm to 10 microns, although certain embodimentsare not limited in this regard. Flexible, transparent electrodes 672 a,672 b (e.g., electrodes 315, 320) may be disposed on opposite sides ofthe accommodation actuator—e.g., where alignment layers 674 a, 674 bprovide at least some isolation to prevent one or more conductive pathsbetween pinch-off region 680 and transparent electrodes 672 a, 672 b.Under control of circuitry 685, electrodes 672 a, 672 b may apply avoltage differential across the accommodation actuator. Alignment layers672 a, 672 b may comprise polyimide or other suitable material toprovide for changing an alignment of liquid crystal molecules to changea refractive index of LC layer 665. In one embodiment, an unpoweredstate of the LC layer 665 allows for distance viewing—e.g., where anynon-zero voltage applied across the liquid crystal layer shortens afocal distance of the eye-mountable device (as compared to a focaldistance of the eye-mountable device without any such voltage applied).

FIGS. 7A-7C illustrate example orientations of an anterior flexibleconductive electrode (ANT) 705 and a posterior flexible conductiveelectrode (POST) 732 within an eye-mountable device 700, in accordancewith an embodiment. FIG. 7A illustrates ANT 705 formed onto the concavesurface of an anterior layer 705, FIG. 7B illustrates POST 732 formedonto the convex surface of a posterior layer 710, and FIG. 7C is a planview illustration of a fully assembled eye-mountable device 700. FIG. 8is a profile illustration of a portion of ring substrate 730 that formselectrical connections to a connection tab 760 of ANT 715 and aconnection tab 765 of POST 732, in accordance with an embodiment.

In the illustrated embodiment, ANT 715 includes connection tab 760 forelectrically connecting to anterior contact pad 745 disposed on thefront side of ring substrate 730. Correspondingly, POST 732 includesconnection tab 765 for electrically connecting to posterior contact pad750 disposed on the backside of ring substrate 730. FIG. 8 illustratesthe use of conductive adhesive 785 to improve the electricallyconnections between connection tabs 760 and 765 and contact pads 745 and750, respectively. Conductive adhesive 785 may be implemented using avariety of different materials, such as, silver loaded epoxies, silicon,or polyurethane, or otherwise. Conductive adhesive 785 providesflexible, conductive adhesion that maintains electrical connection whenthe smart contact lens is bent or folded despite the differentflexibility characteristics of the various constituent parts ofeye-mountable device 700.

In the illustrated embodiment, connection tabs 760 and 765 arerotationally offset relative to each other to make room for athrough-substrate via for one or both of contact pads 745, 765. Forexample, in the illustrated embodiment, power supply 735 and controllercircuit 740 are disposed on the front side of ring substrate 730, thusposterior contact pad 750 is connected to controller circuit 740 using athrough substrate via.

FIG. 7C further illustrates the contour 712 of a LC layer between ANT715 and POST 732. The LC layer may separate ANT 715 and POST 732 fromone another, and may be actuated by voltages applied across theseelectrodes by controller circuit 740. In the illustrated embodiment, theLC layer extends across a larger portion of the center region to ensurethat ANT 715 and POST 732 do not short circuit to each other. In oneembodiment, transparent insulating layers (e.g., polyimide) may befurther applied each to separate the LC layer from a respective one ofANT 715 and POST 732, while in other embodiments ANT 715 and POST 732may form direct contact with the LC layer. Both LC layer 720 andrespective portions of ANT 715 and POST 732—e.g., other than connectiontabs 760, 765—may be contained within the inner radius of ring substrate730 and may not contact the inner edge of ring substrate 730. In oneembodiment, ANT 715 and POST 732 have a diameter of approximately 6 mm,LC layer 725 has a diameter of approximately 7 mm, and the inner edge ofring substrate 730, which defines the center region, has a diameter of 9mm. Of course, other dimensions may be implemented. Anterior layer 705and posterior layer 710 may come in contact with one another to form apinch-off region 720 between diameter of contour 712 and a largerdiameter of the inner edge of ring substrate 730. Pinch-off region 720may variously prevent shorting of the liquid crystal layer, ANT 715and/or POST 732 to at least some circuitry of ring substrate 730.

Techniques and architectures for providing automatic accommodation withan eye-mountable device are described herein. Some portions of thedetailed description herein are presented in terms of algorithms andsymbolic representations of operations on data bits within a computermemory. These algorithmic descriptions and representations are the meansused by those skilled in the computing arts to most effectively conveythe substance of their work to others skilled in the art. An algorithmis here, and generally, conceived to be a self-consistent sequence ofsteps leading to a desired result. The steps are those requiringphysical manipulations of physical quantities. Usually, though notnecessarily, these quantities take the form of electrical or magneticsignals capable of being stored, transferred, combined, compared, andotherwise manipulated. It has proven convenient at times, principallyfor reasons of common usage, to refer to these signals as bits, values,elements, symbols, characters, terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise as apparent from the discussion herein, itis appreciated that throughout the description, discussions utilizingterms such as “processing” or “computing” or “calculating” or“determining” or “displaying” or the like, refer to the action andprocesses of a computer system, or similar electronic computing device,that manipulates and transforms data represented as physical(electronic) quantities within the computer system's registers andmemories into other data similarly represented as physical quantitieswithin the computer system memories or registers or other suchinformation storage, transmission or display devices.

Certain embodiments also relate to apparatus for performing theoperations herein. This apparatus may be specially constructed for therequired purposes, or it may comprise a general purpose computerselectively activated or reconfigured by a computer program stored inthe computer. Such a computer program may be stored in a computerreadable storage medium, such as, but is not limited to, any type ofdisk including floppy disks, optical disks, CD-ROMs, andmagnetic-optical disks, read-only memories (ROMs), random accessmemories (RAMs) such as dynamic RAM (DRAM), EPROMs, EEPROMs, magnetic oroptical cards, or any type of media suitable for storing electronicinstructions, and coupled to a computer system bus.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems may be used with programs in accordance with the teachingsherein, or it may prove convenient to construct more specializedapparatus to perform the required method steps. The required structurefor a variety of these systems will appear from the description herein.In addition, certain embodiments are not described with reference to anyparticular programming language. It will be appreciated that a varietyof programming languages may be used to implement the teachings of suchembodiments as described herein.

Besides what is described herein, various modifications may be made tothe disclosed embodiments and implementations thereof without departingfrom their scope. Therefore, the illustrations and examples hereinshould be construed in an illustrative, and not a restrictive sense. Thescope of the invention should be measured solely by reference to theclaims that follow.

What is claimed is:
 1. An eye-mountable device (EMD) configured forremoveably mounting over an eye surface, the EMD comprising: a lensenclosure including a central region, a peripheral region, a firstencapsulation layer, and a second encapsulation layer, wherein thesecond encapsulation layer is sealed to the first encapsulation layer; aliquid crystal material disposed across the central region of the lensenclosure; a first electrode disposed within the lens enclosure betweenthe first encapsulation layer and the liquid crystal material; a secondelectrode disposed within the lens enclosure between the secondencapsulation layer and the liquid crystal material; a substratedisposed within the EMD; a controller disposed on the substrate andelectrically coupled to the first and second electrodes to apply avoltage across the liquid crystal material; and a pinch-off regiondefining a perimeter of the central region where a portion of the firstencapsulation layer physically contacts a portion of the secondencapsulation layer, wherein the pinch-off region separates the centralregion from the peripheral region.
 2. The EMD of claim 1, wherein thesubstrate is disposed in a peripheral region that extends around atleast a portion of the liquid crystal material in the central region. 3.The EMD of claim 2, wherein the pinch-off region at least partiallyseals the liquid crystal material in the central region.
 4. The EMD ofclaim 3, wherein the pinch-off region comprises a recess disposed in oneof the first or second encapsulation layers that forms physical contactbetween the first and second encapsulation layers to seal the liquidcrystal material in the central region.
 5. The EMD of claim 4, whereinat least one of the first or second encapsulation layer adjacent to therecess forms a taper of the central region that extends in a directiontoward the pinch-off region.
 6. The EMD of claim 4, wherein at least oneof the first or second encapsulation layer adjacent to the recess formsa taper of the peripheral region that extends in a direction toward thepinch-off region.
 7. The EMD of claim 3, wherein the pinch-off regionseparates the liquid crystal material in the central region from thesubstrate in the peripheral region.
 8. The EMD of claim 7, whereinrespective edges of the first and second encapsulation layers are sealedtogether around a perimeter edge of the peripheral region to seal thesubstrate.
 9. The EMD of claim 3, wherein the first electrode includes afirst main body portion and a first connection tab that extends from thefirst main body portion and through the pinch-off region, wherein thesecond electrode includes a second main body portion and a secondconnection tab that extends from the second main body portion andthrough the pinch-off region, wherein the controller is coupled to thefirst and second connection tabs.
 10. The EMD of claim 9, wherein thefirst connection tab and the second connection tab are rotationallyoffset from each other.
 11. The EMD of claim 9, further comprising: afirst contact disposed on a first side of the substrate and coupled tothe controller; and a second contact disposed on a second side of thesubstrate, opposite the first side, and coupled to the controller,wherein the substrate is disposed between the first and secondconnection tabs and wherein the first connection tab overlaps and iscoupled to the first contact and the second connection tab overlaps andis coupled to the second contact.
 12. The EMD of claim 2, furthercomprising: a sensor system disposed within the lens enclosure andcoupled to the controller, wherein the controller includes logic thatwhen executed by the controller causes the controller to performoperations including: monitoring feedback signals from the sensorsystem; determining a gaze direction or a focal distance based upon thefeedback signals; and adjusting the voltage applied across the liquidcrystal material to automatically adjust a level of accommodationprovided by the EMD.
 13. The EMD of claim 12, wherein the sensor systemcomprises a capacitive sensor system that monitors eyelid overlap. 14.The EMD of claim 13, wherein the capacitive sensor system comprises aring of capacitive sensors extending at least partially around theperipheral region.
 15. The EMD of claim 1, further comprising: a firstalignment layer disposed between the liquid crystal material and thefirst electrode, wherein the first alignment layer extends across thecentral region and has a larger area than that of the first electrode;and a second alignment layer disposed between the liquid crystalmaterial and the second electrode, wherein the second alignment layerextends across the central region and has a larger area than that of thesecond electrode, wherein the first and second alignment layers alignmolecules of the liquid crystal material.
 16. The EMD of claim 1,wherein the first and second encapsulation layers comprise a flexiblecontact lens material.
 17. An eye-mountable device (EMD) configured formounting over an eye surface, the EMD comprising: a lens enclosureincluding a first encapsulation layer and a second encapsulation layer,wherein the lens enclosure is curved; a liquid crystal material disposedacross a central region of the lens enclosure; a first electrodedisposed within the lens enclosure between the first encapsulation layerand the liquid crystal material; a second electrode disposed within thelens enclosure between the second encapsulation layer and the liquidcrystal material; a substrate disposed within the EMD, wherein thesubstrate is disposed in a peripheral region that extends around atleast a portion of the liquid crystal material in the central region; acontroller disposed on the substrate and electrically coupled to thefirst and second electrodes to apply a voltage across the liquid crystalmaterial; and a pinch-off region defining a perimeter of the centralregion where a portion of the first encapsulation layer physicallycontacts a portion of the second encapsulation layer, wherein thepinch-off region separates the liquid crystal material in the centralregion from the substrate in the peripheral region.
 18. An eye-mountabledevice (EMD) configured for mounting over an eye surface, the EMDcomprising: a lens enclosure including a first encapsulation layer and asecond encapsulation layer sealed to the first encapsulation layer; aliquid crystal material disposed across a central region of the lensenclosure; a first electrode disposed within the lens enclosure betweenthe first encapsulation layer and the liquid crystal material; a secondelectrode disposed within the lens enclosure between the secondencapsulation layer and the liquid crystal material; a substratedisposed within the EMD, wherein the substrate is disposed in aperipheral region that extends around at least a portion of the liquidcrystal material in the central region; a controller disposed on thesubstrate and electrically coupled to the first and second electrodes toapply a voltage across the liquid crystal material; and a pinch-offregion defining a perimeter of the central region where a portion of thefirst encapsulation layer physically contacts a portion of the secondencapsulation layer, wherein the pinch-off region seals the liquidcrystal material in the central region.
 19. The EMD of claim 18, whereinthe pinch-off region separates the liquid crystal material in thecentral region from the substrate in the peripheral region.